In the pharmaceutical industry it is known to use filling needles for precision transfer of liquids into dosage containers such as vials or ampoules or the like. During such transfer, liquid is supplied at a constant flow rate into the needle channel at one end of the needle and the liquid exits the channel at the other end of the needle. The liquid exits the needle in a continuous stream. In some applications disposable plastics needles are preferred in place of sterilisable metal needles. The nature of plastics materials used for manufacture of disposable needles, and in particular, difficulty in obtaining plastic needles having the same strength characteristics as metal needles gives rise to problems such as control of size and behaviour of liquid droplets which may form at the needle tip at the time when the liquid stream is shut off. Those droplets subsequently separate from the needle tip and fall into the dosage container. This can affect the accuracy of filling dosage containers.
An object of the present invention is to seek to alleviate these problems.